Comparison of physiological effects of fluazifop-butyl and sethoxydim on oat (Avena sativa L.) |
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| Authors: | Xiaoyong Luo Hiroshi Matsumoto Kenji Usui |
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| Institution: | Doctoral Program in Agricultural Sciences and;Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Japan |
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| Abstract: | Laboratory experiments were conducted to compare the physiological effects of two herbicides: fluazifop-butyl {butyl ( RS )-2-4-(5-trifluoromethyl-2-pyridyloxy)phenoxy]-propionate} and sethoxydim {(±)-2-1-(ethoxyimino)butyl]-5-2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} on oat ( Avena sativa L. cv. Zenshin). The herbicides strongly inhibited growth of oat and induced chlorosis at the basal part of shoots and ethylene production from the seedlings. The phytotoxicity of these herbicides in oat seedlings was alleviated by 2,4-D (2,4-dichlorophenoxyacetic acid), but not by IAA (indole-3-acetic acid). Coleoptile elongation induced by 2,4-D or IAA was inhibited by fluazifop-butyl and sethoxydim, suggesting both herbicides possess the activity to inhibit this auxin action. Fluazifop (free acid) and sethoxydim inhibited proton excretion from oat roots but fluazifop-butyl did not. This proton excretion was not restored by 2,4-D or IAA. Furthermore, cellular electrolyte leakage in oat shoots was increased by both herbicides, indicating that the membrane permeability was increased. We conclude that fluazifop-butyl and sethoxydim may have the same mechanism of action which leads to disruption of membrane integrity, although fluazifop-butyl acts as a free acid after hydrolysis (fluazifop). |
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| Keywords: | fluazifop-butyl oat (Avena sativa L cv Zenshin) physiological effects sethoxydim |
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